While Vipp1 (also known as IM30) clearly is essential for proper biogenesis of thylakoid membranes in chloroplasts and cyanobacteria, the exact function of Vipp1/IM30 still remains unclear. The recent in vivo study of Gutu et al. now demonstrates that Vipp1/IM30 forms localized puncta specifically at highly curved membrane regions at the cell periphery. These Vipp1/IM30 puncta were found being highly dynamic under normal growth conditions, while it has recently been shown that they stably associate with membranes under high-light conditions. These observations, together with the observation that other Vipp1/IM30 homologous proteins also form puncta under stress conditions, indicate a protective function of these proteins at stressed membrane regions. However, Gutu et al. additionally show that Vipp1/IM30 is of special importance when growing cells are shifted from dark to light growth conditions, which could be explained by light stress, by thylakoid membrane dynamics and/or by photosystem biogenesis, which is being discussed in this article.
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